Finding old BBM converstion

I desperately need help! I deleted a contact off of my BBM but I need to see our previous conversations that we have had over the last 10 months. I phoned blackberry and they said I cannot. Are the conversations not saved into a media card or if we back up our blackberry on a computer somehow? What about if the other person has me as a contact still? Could I find a conversation that was deleted from their phone months ago? Please help someone....my future is in your hands...

There is an option in BBM which deals with this. If you go to BBM. Press the menu key. Press options. (I'm using a Storm), there is an option that says "Save Chat history:". If its set to "Device" or something other than Never, your messages should be saved to your phone's memory or the media card.